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A, B lock unlocking principle and unlocking method
Dec 04, 2018

A, B lock unlocking principle and unlocking method

A, B key lock, it has two keys A.B. It is a type of lock made up of bullets and other structures. The depth of the pit is different, and the difference between the depth of the flat key is the same.


The role of the A and B keys is that when people install the lock, the owner can hand over the A key to the house decorator for them to enter and exit the house door to unlock, so the A key is also called the “renovation key”. When the decoration is completed, the owner does not need the decoration personnel to enter the room. After the owner inserts the B key into the lock hole and rotates the lock cylinder for one rotation, the A key loses the function of unlocking, so the B key is also called the “homeowner key”.


The advantage of the AB key lock is that it can meet the needs of people to decorate the house, avoiding the loss of the door opening key when the decoration is in a mess, or the person who has a bad heart to copy the door open key, etc., may avoid the owner’s Unsafe factors can also avoid the trouble and cost brought about by the lock after the decoration, so it is welcomed by people.


First, the difference between A and B keys and the working principle of the lock


1. For the sake of easy distinction between the manufacturers, the 6 B keys are packaged in a transparent hard case, and the 2 A keys are hung outside. Some A and B keys have different colors. The 2 A keys are yellow and the 6 B keys are white. There are instructions on the back of the 6 B-key package. The owner should read clearly before use, and recognize the use of the two keys. Do not confuse them to avoid improper use of the two keys.


2. If the two keys A and B are closely observed, experienced people will find that there is a difference between the seven pits above the key. When I say that I want to be inside, I must have an idea. The specific difference is not so convenient for us to say, so I reminded the homeowner that A key must be taken back after use and properly preserved or destroyed.


3. The marble structure in the marble chamber corresponding to the different depths of the A and B keys is special. A steel ball of φ1mm is placed between the upper and lower marbles. When using the A key, the height of the lower marble in the marble chamber plus the height of the small steel ball is exactly flush with the lock core, so the lock can be unlocked with the A key; when the B key is used, the small steel ball can be used. The top lock cylinder, that is to say, the lower bead and the lock core are flush, so the B key can also be twisted and unlocked by the lock core. This principle is the same as the mother key system, and can be small when the lock core is rotated by a certain angle. The steel ball will be under the action of the upper spring, and will fall into the blind hole that has been skillfully designed on the lock core. Some people call this small blind hole a trap, which is very appropriate. The diameter of this blind hole is larger than that of the small steel ball, but it is smaller than the diameter of the marble. Otherwise, the falling of the marble will make the lock cylinder jam and cannot be unlocked. Once the small steel ball falls into the blind hole, it can only rotate with the lock core, and will not run out of the blind hole. It will not affect the use of the B key, but when the A key is used, there is no small steel ball, so the lower part of the marble chamber The marble cannot be flush with the lock core, and the lock cylinder cannot be unlocked.


Second, unlock


1. The lock cylinder is designed to be unlocked outside the door. Therefore, the middle part of the inner and outer lock cylinders is provided with a clutch device. When one side lock core is inserted into the key, the front end of the key will be the top of the plug device on the side. Into the engaging groove in the middle cam, the plugging device in the other side slot can be pushed out of the slot at the same time. When the lock cylinder is twisted, the plugging device drives the cam to move the latch to unlock.


2. There are two ways to position the A and B keys into the depth of the lock cylinder. One is to locate the root of the key; the other is to position the front end of the key. The function of the positioning is that when the key is inserted, the respective beads can be placed in the appropriate pit, and the front end of the key can engage the plug device with the cam to drive the cam to rotate.